Program.cs

using System;
using System.IO;
using System.Threading;
using System.Net;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json;

namespace ConsoleApp6
{
    class Program
    {
        static void Main(string[] args)
        {

            HttpWebRequest req = HttpWebRequest.CreateHttp("http://httpbin.org/ip");
            req.Method = "GET";
            HttpWebResponse res = (HttpWebResponse)req.GetResponse();
            using (Stream stream = res.GetResponseStream())
            {
                StreamReader reader = new StreamReader(stream);
                String s = reader.ReadToEnd();
                Console.WriteLine(s);


                WebClient client = new WebClient();
                client.DownloadFile("http://httpbin.org/image/png", "plik.png");

                client.DownloadFile("http://ipv4.download.thinkbroadband.com/5MB.zip", "plik.zip");
                Console.WriteLine("Skończono!");

                client.DownloadFileAsync(new Uri("http://ipv4.download.thinkbroadband.com/5MB.zip"), "plik.zip");

                client.DownloadFileCompleted += client_DownloadFileCompleted;
                Console.WriteLine("Dalszy ciąg programu...");
                evt.WaitOne();
            }
}
            static ManualResetEvent evt = new System.Threading.ManualResetEvent(false);
            static void client_DownloadFileCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)
            {

                Console.WriteLine("Pobrano plik!");
                evt.Set();
            }
        }

    }